(126a) Experimental and Simulation Studies of Foam in Porous Media At Steady State

In this work, we perform experimental and simulation studies of foam in porous media. Air and surfactant solution (IOS 1518 with a salinity of 1.0% wt NaCl) are co-injected into a silica sand pack with syringe pumps. At a fixed total flow rate, both high-quality and low-quality foam regimes are observed in the experiments with various surfactant concentrations. At steady state, the saturation of aqueous phase in porous media is shown to be strongly dependent on foam strength.

We utilize the STARS foam model in our in-house one-dimensional foam simulator to fit the experimental results. By conducting superposition of the contour plots of the transition foam quality (f_g^*) and the foam apparent viscosity, one can obtain the optimal reference mobility reduction factor (fmmob) and critical aqueous phase saturation (fmdry) in the foam model. This approach provides an alternative to fit the foam model in addition to drawing the pressure contours of the experimental data, which may cause inaccuracy of parameter estimation due to the limited number of data points. Additionally, the effect of surfactant concentration on foam stability is also evaluated experimentally to determine the critical surfactant concentration (fmsurf) and verify the hypothesis in the foam model. In the case of IOS 1518 in silica sand pack, we find that fmsurf is well above the traditional critical micelle concentration (CMC).

With a given surfactant formulation and total injection rate, the presented techniques can be used for prediction of foam apparent viscosity as a function of gas fraction and surfactant concentration, which optimizes the injection strategy for foam enhanced oil recovery (EOR) processes with minimal cost.